Objective: To study possible immunobiological potential of Osmunda japonica Thunb. Results: The extracts activated dose dependently, with the onset at 2.5–5 μ mol/L concentrations, the high output NO production, and secretion of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β).
Conclusion: Phenolic compounds contained in medicinal herb Osmunda japonica possess distinct immunomodulatory activity.